1. Field of the Description
The present invention relates, in general, to hard stops for rotatable joints, and, more particularly, to a hard stop assembly adapted to define a maximum amount of rotation in either direction for a joint adapted and used for rotations greater than 360 degrees (or for more than a single revolution about a rotation axis).
2. Relevant Background
There are many applications where a mechanical device is allowed to rotate more than a full revolution or more than 360 degrees about a rotation axis. For example, there are human operator-to-mechanical system interfaces that are used to translate movement of a human operator's wrist (or other body part) and, in some cases, a master device or remote manipulator into movements or instructions for functionality to a mechanical system. A specific example is a wrist-mounted interface that is ring shaped for a puppeteering device (e.g., an exemplary master device or remote manipulator), with rotational movement of the operator's wrist being measured, tracked, and used as input for the puppeteering device to cause a puppet to move in a particular manner.
Due to the high range of motion of the operator's wrist and of the master device (or remote manipulator) in this exemplary and other examples of rotating mechanical devices, there is a need for a rotating joint (e.g., a rotating wrist) design that allows for more than one revolution (or more than 360 degrees of rotation). A challenge with such rotating mechanical devices, though, is that too much rotation may be undesirable. In the puppeteering or remote manipulator implementation, for example, sensing equipment such as a potentiometer may be provided near or attached to a rotation component (e.g., an inner ring) of the joint, and this sensing equipment may be subject to damage if the joint is “over rotated” such as a rotation through 2, 3, or more revolutions.
Hence, there remains a need for rotation mechanisms that may be used in a variety of settings to provide a rotation range greater than 360 degrees, such as for a rotating wrist joint (or similar human-operator interface apparatus) and that are specially adapted with some form of positive stop in order to prevent over rotation (e.g., prevent 1.5 to 3 revolutions or the like or some other maximum rotation) to prevent over-travel of sensing equipment or wiring on-board the rotation mechanism.